I discovered Wikipedia via a piece I read in the Kuro5hin weblog on 25 Sep 2001. It was exciting to see the energy people were putting into generating and improving the encyclopaedia.
I'm still astounded at the quality of writing that many people are contributing to the entries and in the /Talk areas as well.
More recently most of my energies have been directed to using wikis (mainly UseMod & SnipSnap) as a personal memory and organisation tool and for assisting me to learn a language. Wiki as memory mapper.
Now I'm checking whether I should use MediaWiki for this.